Objective To observe the expression of p53, bcl-2 genes, vascular endothelial cell growth factor（VEGF）, basic fibroblast growth factor（bFGF）, insulin-like growth factor-I （IGF-I）, and the receptors of these factors of retinal vascular endothelial cells (VECs) of 1- to 20-week diabetic rats, and the relationship between the expressions and cell cycle arrest.Methods Retinal sections of diabetic rats induced by alloxan were immunohistochemically stained and observed by light microscopy (LM) and electron microscopy (EM). Dot blotting and Western blotting were used to determine the expression of mRNA, proteins of p53 and bcl-2. Results Under LM, immunohistochemical positive expression of p53 and bcl-2 were found on the vessels of ganglion cell layer and inner nuclear layer of retinae of 8- to 20-week diabetic rats; under EM, these substances were observed depositing in VECs. The retinal VECs also expressed VEGF, bFGF, IGF-I and their receptors. There was no positive expression of other cell types in these retinae, all cell types of retinae in control group, or all cells of retinae of diabetic rats with the course of disease of 1 to 6 weeks. The result of dot blotting revealed that retinal tissue of 20-week diabetic rat expressed p53 and bcl-2 mRNA, and the result of Western blotting revealed that they also expressed p53 and bcl-2 proteins. But retinal tissues of control group did not. Positive expression of bax was not found in the retinae in control group or 1- to 20-week diabetic rats. Conclusion p53, bcl-2 may introduce cell cycle arrest of VECs of retinae in 8- to 20-week diabetic rats. High glucose might stimulate the expression of VEGF, bFGF, IGF-I and their receptors, and the growth factors may keep VECs surviving by self-secretion. (Chin J Ocul Fundus Dis，2003，19：29-33)
ObjectiveTo observe the expression of Caspase-3, Caspase-8, Bcl-2, Bax in the rat retina of ocular ischemic syndrome (OIS).
Methods30 Brown Norway rats were randomly divided into experimental group and control group, 15 rats in each group. The rats in experimental group were established a model through ligating the bilateral common carotid artery. At 3 months after modeling, the retinal thickness and ganglion cell (RGC) density were measured by hematoxylin eosin staining; the expression of Caspase 3, Caspase 8, Bax and Bcl-2 in the retina was measured by quantitative real-time reverse transcription polymerase chain reaction.
ResultsThe RGC density in control group and experimental group was 61.97±9.07 and 38.1±5.98, respectively. Compared to the control group, the RGC density was diminished in the experimental group (t=3.059, P < 0.01). A significant decrease was found in the total retina (t=3.036), inner plexiform (t=3.715), inner nuclear (t=3.339) and outer plexiform (t=3.341) thickness (P < 0.05). However, no change of the thickness was evident in the outer nuclear layers (t=2.000, P > 0.05). The levels of protein and RNA expression of Caspase 3, Caspase 8 and Bax in the retina were increased in experimental group (F=17.036, 7.787, 11.431, 11.162, 17.763, 12.183; P < 0.05), while the Bcl-2 expression were decreased (F=10.298, 12.047; P < 0.05).
ConclusionsThere is obvious expression of apoptosis-associated proteins in the rat retina of OIS. Caspase 3, Caspase 8 and Bax expression are increased, while Bcl-2 expression are decreased.
Objective To observe the effects of δ-opioid receptor agonists D-Ala2-D-Leu5-enkephali （DADLE） on hepatocyte apoptosis and expressions of bcl-2 and caspase-3 in septic rat, and to investigate the possible mechanism by which DADLE protects the liver in sepsis. Methods Sepsis was reproduced in rats by cecum ligation and puncture (CLP). Fifty-four SD rats (either male or female) were randomly divided into CLP group (n=18), DADLE group (n=18) and sham operation (SO) group (n=18). The rats were respectively killed at different time (2 h, 4 h and 6 h after operation). Hepatocyte apoptosis was detected by TdT-mediated dUTP Nick End Labeling (TUNEL). The expressions of bcl-2 and caspase-3 protein were detected by immunohistochemistry. And the changes of pathology in hepatic tissue were detected by light microscope. Results The hepatic pathological lesion of rats in CLP group was obviously serious compared with SO group, while it was obviously improved in DADLE group. The apoptosis index of rat hepatocytes in CLP group significantly increased compared with SO group, and further it was prominent at 4 h （P＜0.01). The apoptosis index of rat hepatocytes at each time of DADLE group was significantly decreased compared with CLP group （P＜0.01）. Expression of caspase-3 protein in liver tissues of CLP group significantly increased compared with SO group （P＜0.01）, while the expression of bcl-2 protein significantly decreased （P＜0.05）. Expression of caspase-3 protein in liver tissues of DADLE group significantly decreased compared with the CLP group （P＜0.01）, while the expression of bcl-2 protein significantly increased （P＜0.05）. There was positive correlation between expression of caspase-3 in liver tissues and apoptosis index of hepatocyte (r=0.83, P＜0.01) and negative correlation between expression of bcl-2 in liver tissues and apoptosis index of hepatocyte (r=-0.65, P＜0.01). Conclusions The findings indicate that δ-opioid receptor agonists DADLE can obviously improve hepatic pathological changes of septic rats. And its protective mechanism contains down regulation of caspase-3 expression, upregulation of bcl-2 expression and thus the apoptosis of hepatocyte is repressed.
Objective To study the inhibitory effect of RNA interference (RNAi) on bcl-2 expression of vascular smooth muscle cells （VSMCs) in rabbit. Methods The expression vector of bcl-2 gene-targeting small interference RNA (pshRNA-bcl-2) was constructed and was transfected into VSMCs by lipofectamine, and the unloaded vector was used as control. The expression of bcl-2 mRNA was identified by RT-PCR and Western blot, respectively. The growth of the transfected VSMCs was examined by MTT. Results The pshRNA-bcl-2 may inhibit the expression of bcl-2 gene at the levels of transcription and translation. There were significant differences (P＜0.01) of the expressions of bcl-2 mRNA between the VSMCs that were transfected with pshRNA-bcl-2 and the ones in plasmid transfected group and control group, respectively. There was a significant difference (P＜0.01) in the growth of VSMCs between the plasmid transfected and the control groups. Conclusion The plasmid containing the small interference RNA of bcl-2 may have an inhibitory effect on the cell growth and endogenous expression of bcl-2 gene at the levels of transcription and translation in VSMCs.
Objective The expression of CD15 antigen and oncoprotein bcl-2 in thyroid cancer were examined in order to study the correlation between them. Methods The expression of CD15 and bcl-2 in 50 thyroid cancers, 20 adjacent noncancerous portion, 45 adenoma and 10 normal thyroid tissue were respectively investigated by microwave-LSAB immunohistochemical technique. Results The positive rate of CD15 and bcl-2 in thyroid cancer was 68.0% and 46.0% respectively, which was significantly higher than that in adenoma or adjacent noncancerous (Ｐ＜0.05). The percentage of CD15 and bcl2 positive expression were found to be significantly correlated with the tumor metastasis (Ｐ＜0.05), but not correlated with histological feature. Expression of CD15 was significantly correlated with bcl-2.Conclusion Expression of CD15 and bcl-2 can be regarded as a parameter to evaluate tumor metastasis and prognosis of thyroid cancer.
Objective To investigate the effect of renal cell apoptosis induced by obstructive jaundice on the expression of bcl-2 in rats, and to explore the mechanism of renal impairment induced by obstructive jaundice. Methods Thirty-two male SD rats were randomly divided into 2 groups: SO group and BDL group. The rats in SO group received sham operation. Bile ducts of rats in BDL group were ligated. Pathology of kidneys was observed under the microscope. The levels of D-Bil, TBA, GOT, GPT, Cr and BUN in serum and β2-MG in urine were measured. The apoptotic rate of renal cells was calculated by flow cytometry and the forms of DNA fragmentation in renal cells were detected by agarose gel electrophoresis. The expression of inhibitory gene bcl-2 in the renal tissues was detected by immunohistochemistry. Results The color of urine in BDL group became dark yellow in day 2 after operation; The ears, tails and the muscle of abdominal wall and splanchnic organs, such as liver and kidney, also became yellow and swollen in day 7. The D-Bil, TBA, GOT, GPT, BUN of serum and β2 -MG of urine in BDL group were higher than those in SO group (P＜0.05, P＜0.01), and each value (except β2 -MG) in BDL group of 14 d was higher than that in BDL group of 7 d (P＜0.05, P＜0.01), respectively. The result of flow cytometry showed that the apoptotic rate of SO group and BDL (7 d and 14 d) group were (2.10±0.75)%， (18.17±0.86)% and (36.39±2.23)% respectively, there were significantly difference among them (P＜0.05). The expression rate of bcl-2 of renal cell in BDL group of 7 d was higher than that in BDL group of 14 d. Conclusion Obstructive jaundice could induce apoptosis of the renal cells, and activate the expression of bcl-2 of the renal tubular epithelial cells in feedback, which may regulate the process of apoptosis.
To elucidate bcl-2 protein expression in hepatic carcinogenetic process and its relationship with apoptotic changes. bcl-2 protein was evaluated immunohistochemically while apoptosis was approached with terminal deoxynucleotidyl transferase (TdT)mediated dUTP nick end labeling (TUNEL) technique in 8 normal livers (NL), 17 liver cirrhosises (LC) and 77 hepatocellular carcinomas (HCC). The results showed that bcl-2 protein was expressed in 3 of 8 NLs(37.5%), 5 of 17 LCs(29.4%) and 7 of 77 HCCs(9.1%) with significant differences between group NL and HCC and between LC and HCC (Ｐ＜0.05). Apoptosis rates of 1.18±0.42%, 4.85±2.78%, 12.89±2.33% in NL, LC, HCC group respectively were demonstrated with significant differences among them (Ｐ＜0.01). Compared the bcl-2 expression with the apoptosis rate in this hepatocarcinogenetic process, reversed trends were presented. Conclusion: bcl-2 expression could be detected in NL, LC and HCC, and its decreasing expression was related to the inhibition attenuation of hepatocellular apoptosis in the process of hepatocarcinogenesis.
Objective To explore the expression of survivin gene in retinoblastoma (RB) and its relationship with the stages and histodifferentiation degree of RB and the expression of p53、bcl-2 proteins. Methods Expression of survivin, p53 and bcl-2 proteins in 38 RB conventional paraffin samples were detected with survivin, p53 and bcl-2 monoclonal antibodies respectively by immunohistochemical assay. The expression of survivin of normal retina in 6 control samples was observed. Results In 38 cases of RB, positive expression of survivin was found in 20 (52.6%); while none of the 6 normal retinal tissue expressed survivin, which had significant difference between the two group (P＜0.05). The positive expression of survivin did not correlate with sex of patient, disease stages and histological type (P＞0.05). In 38 RB cases, positive expression of p53 was in 25 with the rate of 65.8%, and of bcl-2 in 18 with the rate of 47.4%. The positive-expressed rates were much higher in positive-expressed p53 and bcl-2 group than those in the negative-expressed p53 and bcl-2 group(P＜0.05). Conclusion The increase of the expression of survivin implies that it may take part in the occurrence and development of RB; the interaction among survivin, p53 and bcl-2 may participate in the access and the course of RB. (Chin J Ocul Fundus Dis，2004，20：215-217)
Objective
To investigate the molecular mechanism of apoptosis in cultured human retinal pigment epithelial (RPE) cells.
Methods
The growth media of confluency human RPE cells were replaced with a daunoblastinacontaining one at a dose of 180mu;g/L,and the cells were incubated for 12 hr at 37℃.After incubation with the drug,the medium was withdrawn,fresh medium was added and incubation was carried out for an additional 24 hr.Apoptosis was monitored by light microscopy,enzyme linked immunosorbent assay(ELISA)and terminal deoxynucleotidyl transferase mediated biotin-dUTP nick-end labelling(TUNEL)staining.The expression of bax and bcl-2 were evaluated by immuncoytochemical staining with anti-human bcl-2 and bax antibodies.
Results
After the RPE cells treated with daunoblastina,shrinkage of cytoplasm and nucleus was identified.The ratio of nucleus to cytoplasm was increased.TUNEL staining showed that many cells were positive staining.The amount of apoptotic cells was directly proportional to the drug dose.The integral optical desity values for expression of bax inereased by 22.0%(Plt;0.05), and that of bcl-2 did not change significantly(Pgt;0.05).
Conclusions
During human RPE cell apoptosis induced by daunoblastina,overexpression of bax or low bcl-2/bax ratio were demonstrated.The results suggest that bax and bcl-2 gene expression could play a role in regulation of RPE cell apoptosis.
(Chin J Ocul Fundus Dis, 1999, 15: 153-156)
Objective
To study the expression and its significance of bcl-2 associated death (bad) gene in human optic nerves from traumatic atrophic eyeballs.
Methods
The optic nerves from 8 normal human donor eyes and 31 traumatic atrophic eyes were studied by immunohistochemistry technique.
Results
Bad protein was positively expressed in the normal optic nerve myelin sheath and residual myelin portions of optic nerve tissues from traumatic atrophic eyes. The expression of bad protein in the residual portions of myelin sheath was stained significantly ber than that in normal optic nerves (P＜0.05)。The pathological durations for ocular atrophy was not co-related with the quantites of expression of bad protein. There was no significant difference between pathogenic causes of ocular atrophies and the quantites of bad expression (P＞0.05).
Conclusion
Bad might possess the function of promoting the optic nerve atrophy processes in traumatic atrophic eyes.
(Chin J Ocul Fundus Dis, 2002, 18: 276-278)
